A recent dinner at the new GM Burger Bar in Rockville Centre proved something of a mixed experience. Looks here isn’t an issue. The place is ruggedly handsome, in the manner of all the George Martin Group restaurants. And it was hopping the night I went. Lines out the door as well as sidewalk dining. Here, the crew seemed more intent on getting people in and than on getting things right. A “Frenchy”...

Here, the crew seemed more intent on getting people in and than on getting things right. A “Frenchy” burger, which a companion requested medium-rare, arrived somewhere between medium and well-done. The waiter pointed out there was at least a little bit of pink at the center and didn’t offer to have it redone. Topped with onions caramelized in sherry, Gruyere and mozzarella, it came with onion-beef jus on the side. Lots of flavor — and moisture everywhere, except the actual burger. And the sourdough roll it was served on was so big and thick, it had to be abandoned for knife and fork. Cottage fries on the side were better than an order of hand-cut shoestring fries, which lacked crispness as well as flavor. Great pickles on the side. Pretty good chili lime slaw.

A specialty here is the “Juicy Lucy” burger ($14.95), stuffed with bacon and three cheeses, basted with Worcestershire and served on a brioche roll. A panoply of bold flavors. Still, you can’t get it medium-rare, since, we were told, the cheese wouldn’t be hot enough to melt. Not bad but far from juicy. Hard to tell which was drier — the "Pilgrim" turkey burger or the multigrain roll it was served on.

Best was a simple 5-ounce burger, done to temperature and served on a soft hamburger bun you might actually be able to get your mouth around.